1. Field of the Invention
A method is proposed for customer personalization of GSM chips which assumes that the chip at the time of the personalization is located in the terminal equipment of the customer.
According to the present state of the art, the network operators presently implement the GSM chip in a GSM card which is inserted in the terminal equipment. The chip may also be permanently integrated in the terminal equipment, for example, on a plug-in card of a computer. It is not important for the present method if a GSM card or a terminal with an integrated chip is employed. A “chip” in the broadest sense is understood to be an EPROM, an EEPROM, as well as an “intelligent” microprocessor.
Regardless of a particular embodiment, the following discussion will use the term “chip” and “chip manufacturer.”
With centralized personalization used until now, the chip receives, aside from other data, a card number (ICCID), a subscriber identification number (IMSI) as well as several secret numbers. While the chip manufacturer can easily apply the data ICCID and IMSI to the chip, the network operator likes to keep control over the secret numbers, in particular over the key Ki, which should be known only to the card and the network.
With the present centralized personalization, the network operator receives from the card manufacturer unmarked cards and subsequently writes the final secret key.
Accordingly, this key is only known to two localities, namely the chip itself and the network operator.
Disadvantageously, an extraordinarily large static load is produced in the computer center of the network operator. A generator generates a large number of keys which are then applied to the respective cards. The key generated for each card is then simultaneously transmitted to the computer center (authentication center AC), whereafter the card is issued to the sales organization. The AC therefore has already stored all subscriber identification numbers IMSI and the associated secret keys Ki at the time the respective card is issued and has to administer these identification numbers and keys, although the respective card has not yet been sold and is still in the possession of the vendor. Consequently, cards which have not yet been sold are stored in large numbers of sales offices, while the data of these cards have to be administered by the AC.
In addition, it may happen that when a manufacturer or another member of the sales organization attempts to personalize the cards, the key may have already be compromised. The initial personalization of the chip is therefore not secure and may be subject to misuse.
2. Description of the Related Art
EP-A-562 890 discloses a mobile communication network having the capability for remotely updating a so-called subscriber identification module (SIM) in mobile stations. The SIM stores data for controlling the mobile stations and for access to the services of the mobile radio network. The data stored in the SIM can be changed, i.e., updated, over the radio air interface. However, a method for personalizing a SIM over the air interface is not described.
WO-A-97/14258 also describes a method and a device for programming a mobile station via an air interface. Optionally, programs stored in the mobile station are here replaced or additional data are transmitted via the air interface. The method described herein also permits an initial activation of the mobile station via the air interface, but not a personalization of a subscriber identification module.
WO-A-93/07697 relates to a method for personalizing an active so-called SIM card. The SIM card is here completely personalized in an authorized terminal equipment which is connected via an encrypted communication line with a the central computer of the mobile radio network. However, a personalization of the chip card when the subscriber first logs on to the mobile radio network, is also neither taught nor suggested by this reference.
It is therefore an object of the invention to improve a method, a device and a chip of the aforedescribed type so that the overly complex administration in the AC can be simplified and the secret data of the chip can be stored more securely.
To solve the object, the invention is characterized by the technical teachings of claim 1. A chip according to the invention is characterized by the technical teachings of claim 6.